1. Technical Field
The present invention relates to a sealant drawing method, to a sealant drawing apparatus, and to a method and apparatus for manufacturing liquid crystal devices, and in particular, to a manufacturing technology suitable to a case where sealant with a high viscosity is used.
2. Related Art
In general, in the process of manufacturing liquid crystal devices, a panel structure in which two substrates are adhered together using sealant and a liquid crystal material is enclosed therebetween is constructed. This manufacturing process includes a sealant coating process of forming a liquid crystal material enclosure region that contains a liquid crystal material by coating the sealant in such a way as to surround electrode patterns, such as transparent electrodes formed on an inner surface of the substrate. In the sealant coating method in this process, a screen-printing method has been widely used, especially, in the case where sealant having a low viscosity can be used.
However, the screen-printing method is problematic in that nonconformity sometimes occurs since the screen is brought in contact with the inner surface of the substrate. To avoid this problem, there has been proposed a method of drawing a desired pattern on the substrate by discharging the sealant from a nozzle using a dispenser.
In a method using a dispenser, a dispenser is generally used in which sealant is stored in a syringe and a nozzle having a discharge port is provided at the tip of the syringe. The dispenser generally has a construction in which the sealant is mechanically pushed out by an extrusion rod inserted into the syringe, a construction in which the sealant is pushed out by means of the pressure of air supplied into the syringe, and the like. Furthermore, in a method of pushing out sealant by means of air pressure, it is difficult to uniformly discharge sealant having a high viscosity. To avoid this problem, it is conceivable to provide a sealant drawing method using a dispenser through control of a servomotor as a method of discharging sealant (see, e.g., JP-A-2004-290885).
In the case of manufacturing a liquid crystal device by drawing sealant having a high viscosity, as in JP-A-2004-290885, however, if the drawing start position and the drawing end position of the sealant overlap each other, a defective cell gap is likely to occur due to the thickness of the sealant. In addition, since each sealant needs to be formed to surround the liquid crystal material enclosure region, the drawing start and the drawing end have to be performed according to the number of corresponding liquid crystal material enclosure regions. Therefore, it is difficult to draw the sealant in a short period of time.